PURPOSE: To explore if the diameter of an occluded superficial femoral artery (SFA) can predict the technical success of percutaneous recanalization. METHODS: Two hundred patients (151 men; mean age 57 +/- 16 years) suffering from peripheral arterial occlusive disease were evaluated with duplex ultrasonography to measure arterial diameters and percent diameter reduction. Seventy-nine (39.5%) patients had segmental or complete SFA occlusions that ranged in age from 2 to 26 months (median 11). The majority of occlusions (45, 57.0%) were < or =10 cm long (range 10-35). Percutaneous recanalization was performed in 71 patients using either conventional angioplasty or local low-dose thrombolysis with rtPA. RESULTS: Diameters of 79 unilaterally occluded SFAs at the level of occlusion were 4.5 +/- 1.4 mm versus 5.7 +/- 1.3 mm for the patent contralateral artery (p=0.055). None of the 121 patent SFAs had diameters < or =3.5 mm, but 12 (15%) of the 79 occluded SFAs did, and none of these could be recanalized. The sensitivity of the 3.5-mm cut point to predict recanalization failure was 44% (specificity 100%). CONCLUSIONS; Our data suggest that occluded SFAs with a diameter reduction to < or =3.5 mm are not suitable for percutaneous recanalization, as the original arterial lumen cannot be reconstructed.